Abstract
Purpose: :
To correlate peripapillary retinal nerve fiber layer (ppNFL) loss and visual fields (VF) defects in nonarteritic anterior ischemic optic neuropathy (NAION).
Methods: :
Patients with at least one eye affected by AION were scanned with the Nerve Head Map 4mm (NHM4) pattern on the RTVue (Optovue, Inc) Fourier-domain optical coherence tomography (FD-OCT) system. The NHM4 contains 12 radial scans with diameter 4mm and 6 circular scans with diameters from 2.5 to 4mm. ppNFL thickness maps were obtained from the NHM4 scans using automated image processing. ppNFL thickness was averaged in hemispheric, quadrant and octant divisions. VF was tested using the Humphrey Field Analyzer (Carl Zeiss Meditec, Inc.) using the 24-2 program. The VF pattern deviation (PD) and total deviation (TD) were averaged by hemispheres. Pearson’s coefficient R was used to measure the correlation between continuous variables and Chi-square test was used to measure correlation between dichotomous variables (positive versus negative superior - inferior difference).
Results: :
In the 9 patients with unilateral NAION the affected eyes showed significant decrease of ppNFL thickness relative to the nonaffected eyes in the overall average (p=0.01), superior quadrant (p=0.001), and the two superior octants (p<0.01). Using all 19 NAION eyes, we found significant correlations between VF and ppNFL. Mutivariate analysis showed that the superior ppNFL and inferior VF had the best correlation (p=0.01 for PD and p<0.001 for TD respectively). The superior and inferior hemisphere difference (SID) of PD and ppNFL also showed good correlation (R=-0.49, p=0.03; Chi-square test p=0.03).
Keywords: nerve fiber layer • neuro-ophthalmology: diagnosis